Sorted it. Bizarre. I discovered how to generate a new API for the site. However, when I fill the new number into Pro Maps For Google, it gives me every indication it has accepted the new number but when I look at the code, it hasn't!! So, I just copied and pasted the new API number into the code view in DWCS4 and it worked.
Latest version of PMFG, by the way.
Any ideas why it might not write the new API into the relevant line of code?
It's working now, so only look into this in a idle moment.